/*
* Copyright (C) 2013 Doubango Telecom <http://www.doubango.org>
* License: GPLv3
* This file is part of Open Source "thialgou" project <http://code.google.com/p/thialgou/>
*/
#include "io_md5.h"

#include <string.h>
#include <stdlib.h>

static void hl_str_from_hex(const uint8_t *hex, size_t size, char* str)
{
    static const char *HL_HEXA_VALUES = {"0123456789abcdef"};
    size_t i;

    for (i = 0 ; i<size; i++) {
        str[2*i] = HL_HEXA_VALUES [ (*(hex+i) & 0xf0) >> 4 ];
        str[(2*i)+1] = HL_HEXA_VALUES [ (*(hex+i) & 0x0f)		];
    }
}

#define HL_MD5_DIGEST_CALC(input, input_size, digest)		\
	{														\
		hl_md5context_t ctx;								\
		hl_md5init(&ctx);									\
		hl_md5update(&ctx, (const uint8_t*)(input), (input_size));			\
		hl_md5final((digest), &ctx);						\
	}

typedef struct hl_md5context_s {
    uint32_t buf[4];
    uint32_t bytes[2];
    uint32_t in[16];
}
hl_md5context_t;

void hl_md5init(hl_md5context_t *context);
void hl_md5update(hl_md5context_t *context, uint8_t const *buf, size_t len);
void hl_md5final(hl_md5digest_t digest, hl_md5context_t *context);
void hl_md5transform(uint32_t buf[4], uint32_t const in[HL_MD5_DIGEST_SIZE]);
int hl_md5compute(const char* input, size_t size, hl_md5string_t *result);

#if defined(_BIG_ENDIAN)
void hl_byteReverse(uint32_t *buf, unsigned words)
{
    uint8_t *p = (uint8_t *)buf;

    do {
        *buf++ = (uint32_t)((unsigned)p[3] << 8 | p[2]) << 16 |
                 ((unsigned)p[1] << 8 | p[0]);
        p += 4;
    }
    while (--words);
}
#else
#define hl_byteReverse(buf,words) /* do nothing*/
#endif

void hl_md5init(hl_md5context_t *ctx)
{
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

    ctx->bytes[0] = 0;
    ctx->bytes[1] = 0;
}

void hl_md5update(hl_md5context_t *ctx, uint8_t const *buf, size_t len)
{
    uint32_t t;

    /* Update byte count */

    t = ctx->bytes[0];
    if ((ctx->bytes[0] = t + len) < t) {
        ctx->bytes[1]++;    /* Carry from low to high */
    }

    t = 64 - (t & 0x3f); 	/* Space available in ctx->in (at least 1) */
    if (t > len) {
        memcpy((uint8_t *)ctx->in + 64 - t, buf, len);
        return ;
    }
    /* First chunk is an odd size */
    memcpy((uint8_t *)ctx->in + 64 - t, buf, t);
    hl_byteReverse(ctx->in, 16);
    hl_md5transform(ctx->buf, ctx->in);
    buf += t;
    len -= t;

    /* Process data in 64-byte chunks */
    while (len >= 64) {
        memcpy(ctx->in, buf, 64);
        hl_byteReverse(ctx->in, 16);
        hl_md5transform(ctx->buf, ctx->in);
        buf += 64;
        len -= 64;
    }

    /* Handle any remaining bytes of data. */
    memcpy(ctx->in, buf, len);
}

void hl_md5final(hl_md5digest_t digest, hl_md5context_t *ctx)
{
    int count = ctx->bytes[0] & 0x3f; 	/* Number of bytes in ctx->in */
    uint8_t *p = (uint8_t *)ctx->in + count;

    /* Set the first char of padding to 0x80.  There is always room. */
    *p++ = 0x80;

    /* Bytes of padding needed to make 56 bytes (-8..55) */
    count = 56 - 1 - count;

    if (count < 0) {
        /* Padding forces an extra block */
        memset(p, 0, count + 8);
        hl_byteReverse(ctx->in, 16);
        hl_md5transform(ctx->buf, ctx->in);
        p = (uint8_t *)ctx->in;
        count = 56;
    }
    memset(p, 0, count);
    hl_byteReverse(ctx->in, 14);

    /* Append length in bits and transform */
    ctx->in[14] = ctx->bytes[0] << 3;
    ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
    hl_md5transform(ctx->buf, ctx->in);

    hl_byteReverse(ctx->buf, 4);
    memcpy(digest, ctx->buf, 16);
    memset(ctx, 0, sizeof(*ctx)); 	/* In case it's sensitive */
}

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f,w,x,y,z,in,s) \
(w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)

void hl_md5transform(uint32_t buf[4], uint32_t const in[HL_MD5_DIGEST_SIZE])
{
    register uint32_t a, b, c, d;

    a = buf[0];
    b = buf[1];
    c = buf[2];
    d = buf[3];

    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

    buf[0] += a;
    buf[1] += b;
    buf[2] += c;
    buf[3] += d;
}

int hl_md5compute(const char* input, size_t size, hl_md5string_t *result)
{
    hl_md5digest_t digest;

    if(!result | !*result) {
        return -1;
    }

    (*result)[HL_MD5_STRING_SIZE] = '\0';

    HL_MD5_DIGEST_CALC(input, size, digest);
    hl_str_from_hex(digest, HL_MD5_DIGEST_SIZE, *result);

    return 0;
}

Md5::Md5()
{
	m_pCtx = (struct hl_md5context_s*)malloc(sizeof(struct hl_md5context_s));
	init();
}

Md5::~Md5()
{
	free(m_pCtx);
}

void Md5::init()
{
	hl_md5init(m_pCtx);
}

void Md5::update(const void* p_ptr, size_t u_size)
{
	hl_md5update(m_pCtx, (uint8_t const *)p_ptr, u_size);
}

const char* Md5::final()
{
	hl_md5digest_t digest;
	hl_md5final(digest, m_pCtx);
	hl_str_from_hex(digest, HL_MD5_DIGEST_SIZE, m_result);

	return (const char*)m_result;
}

const char* Md5::compute(const void* p_ptr, size_t u_size)
{
	hl_md5compute((const char*)p_ptr, u_size, &m_result);
	return (const char*)m_result;
}
